Ask the Doctors

Dear Doctor: My teenager drinks a lot -- I mean, a LOT -- of soda and energy drinks. But I recently read that a teenager died after only three caffeinated drinks. How can this be? How much is too much?

Dear Reader: I understand your concern. The increase in caffeine consumption in our society coincides with the frenetic pace of modern life. Not too long ago, the majority of Americans caffeinated themselves with a cup of coffee at a diner, coffee house, home or work. Now, we have national chains of coffee shops; iced coffees and teas in every grocery store, drugstore and gas station; and an array of caffeinated sodas lining the aisles of supermarkets.

As if the preponderance of coffees and sodas weren't enough, energy drinks have rapidly permeated our culture. Not only do they contain caffeine, they include stimulants such as taurine, guarana and ginseng, as well as large amounts of sugar. These energy drinks are marketed to young adults, especially men, to help general performance. A 2010 survey of U.S. troops in Afghanistan found that 44.8 percent drank at least one energy drink per day. Within the U.S., an estimated 31 percent of those ages 12 to 17 consume energy drinks regularly, with 5 percent of high school students drinking at least one energy drink per day.

Some people rightfully point out that coffee has been linked to health benefits, specifically to a reduction of heart attacks and strokes. But that data isn't as clear-cut as you might think. A 2014 review of 36 studies showed a 5 to 15 percent reduction in the rates of cardiovascular disease among coffee drinkers compared with people who drank no coffee. (Note that one of the authors received a grant from Nestea, part of the Nestle Company.)

Then there was a 2009 study that followed 83,076 nurses and their caffeine intake; it found a 19 percent reduction in stroke among the nurses who drank two to three cups of coffee per day and a 20 percent reduction among the nurses who drank four or more cups of coffee per day.

However, a 2013 study that followed 43,727 men and women for 17 years found an increase in death rates among those who drank four or more cups of coffee per day, and a 21 percent increase in death rates among men who drank four or more cups of coffee per day. Looking further into the data, the authors found that the increase in death rates was seen only for women and men under age 55 who drank coffee, not in those over 55 who drank coffee. In fact, men younger than 55 who drank four or more cups of coffee per day had a 56 percent increase in the death rate.

All told, it's possible that caffeine has a particularly negative effect upon younger people and that the studies in older adults didn't identify this increased death rate in younger people. It's also possible that older adults who drink caffeine consistently are heartier than their younger counterparts who die for reasons unknown.

This brings us back to teenagers who consume sodas, coffees and energy drinks. There are no good studies for this age range, just the unfortunate case reports of teenagers consuming too many energy drinks and developing life-threatening heart rhythms.

My feeling is that moderation can easily lead to excess within our society, and the best way to deal with this is to describe not only the theoretical risk of sudden death with binge drinking, but the obesity and diabetes that sugary drinks can create. I would recommend against buying these drinks for the home -- and encouraging your teenager to use only one of these types of drinks per day.